Convert ULID to and from UUID in Python

convert_ulid_to_uuid.py

#!/bin/env python3
# @author: Fabio Lima
# @created: 2022-02-10

base16 = '0123456789abcdef'
base32 = '0123456789ABCDEFGHJKMNPQRSTVWXYZ'

def encode(number, alphabet):
	text = ''
	radix = len(alphabet)
	while number:
		text += alphabet[number % radix]
		number //= radix
	return text[::-1] or '0'

def decode(text, alphabet):
	number = 0
	radix = len(alphabet)
	for i in text:
		number = number * radix + alphabet.index(i)
	return number

def to_uuid(ulid):
	
	# decode from base-32
	number = decode(ulid, base32)
	
	# encode the number to base-16
	text = encode(number, base16)
	
	# add hyphens to the base-16 string to form the canonical string
	return text[0:8] + '-' + text[8:12] + '-' + text[12:16] + '-' + text[16:20] + '-' + text[20:32]
	
def to_ulid(uuid):
	
	# remove hyphens from the canonical
	# string to form the base-16 string
	uuid = uuid.replace('-', '')
	
	# decode from base-16
	number = decode(uuid, base16)

	# encode the number to base-32
	return encode(number, base32)

def main():

	ulid_in = '5JRB77HQYQ8P08BWPJRF5Q7F06'
	uuid_in = 'b2c2ce78-dfd7-4580-85f2-d2c3cb73bc06'

	uuid_out = to_uuid(ulid_in)
	ulid_out = to_ulid(uuid_in)

	print('ULID in: ', ulid_in)
	print('ULID out:', ulid_out)
	print('UUID in: ', uuid_in)
	print('UUID out:', uuid_out)

if __name__ == '__main__':
	main()

# Notes:
# 1. A standard UUID has 6 fixed bits: 4 in the version field and 2 in the variant field.
# 2. You must validate the UUID or ULID befor using to_ulid() and to_uuid(). Use REGEX.

Output of the script:

ULID in:  5JRB77HQYQ8P08BWPJRF5Q7F06
ULID out: 5JRB77HQYQ8P08BWPJRF5Q7F06
UUID in:  b2c2ce78-dfd7-4580-85f2-d2c3cb73bc06
UUID out: b2c2ce78-dfd7-4580-85f2-d2c3cb73bc06